JPH0241987Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a flat speaker used in various types of audio equipment.

Conventional configuration and its problems Generally, a flat speaker is configured as shown in FIG. That is, center pole 1
A ring-shaped magnet 3 is placed on a plate 2 having a
A frame 6 is connected to a magnetic circuit 5 constructed by stacking ring-shaped upper plates 4 in the same manner as in the above, and a free edge 8 is connected to the peripheral edge of the frame 6 along with a gasket 7 by adhesive or the like. A flat plate type diaphragm 9, which is constructed by pasting a thin surface material such as aluminum foil on both sides of a core material in which cells are continuously formed, is coupled together, and a coupling cone 10 is bonded to the lower surface of this flat plate type diaphragm 9. A voice coil 12 whose intermediate portion is supported by a damper 11 is coupled to the center of this coupling cone 10, and this voice coil 12 is fitted into the magnetic gap 13 of the magnetic circuit 5 without eccentricity. has been done.

With such a configuration, in order to provide linearity to the vertical amplitude movement of the flat plate diaphragm 9 during operation, the free edge 8 is made of moltoprene rather than fabric impregnated with thermosetting resin. It was constructed using flexible foam.

By using this free edge 8, a product with stable characteristics can be obtained.

However, in the flat diaphragm 9 of the conventional flat speaker, as shown in FIG.
5 and 16, when the flat plate-shaped diaphragm 9 makes a large amplitude movement, the free edge 8 becomes stretched and bulges as shown in FIG. In such a case, the free edge 8 strongly hits the edge of the surface material 15 on the side to which the free edge 8 is pasted, and the edge of the surface material 15 becomes a knife edge that destroys the free edge 8, resulting in poor reliability in terms of resistance to force. It had become a thing.

Purpose of the invention The present invention eliminates the above-mentioned drawbacks of the conventional speaker, and provides a highly reliable flat speaker in which the free edge is not destroyed by the surface material even when the free edge is stretched at a large amplitude. The purpose is to

Structure of the invention In order to achieve the above object, the present invention is a flat plate constructed by attaching a free edge made of soft foam to the periphery of a frame connected to a magnetic circuit, and pasting a thin surface material on both sides of the core material to the free edge. A voice coil that fits into the magnetic gap of the magnetic circuit is connected to this flat diaphragm, and the surface material on the side where the free edge of the flat diaphragm is pasted is slightly larger than the outer diameter of the core material. death,
The part protruding outward from the core material is bent to an angle at which it will not come into contact with the free edge when it is extended by a large amplitude.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 4 and 5.

The structure of the flat speaker is the same as that shown in FIG. 1, and the flat diaphragm, which is a feature of the present invention, will be explained here. Also, the constituent parts of the flat plate type diaphragm are substantially the same as those shown in the conventional FIGS. 2 and 3, and will be described with the same reference numerals.

First, in Figures 4 and 5, 14 is a core material made of a large number of strips of aluminum foil pasted together to form continuous hexagonal cells, or a lightweight and highly rigid foam. The top and bottom surfaces of this core material 14 are coated with a surface material 1 such as aluminum foil.
5 and 16 are attached. This surface material 15,
16, the surface material 15 to which the free edge 8 is attached is formed to be slightly larger than the outer diameter of the core material 14, and the portion 15a of this surface material 15 that protrudes outward from the core material 14 is directed downward at an angle θ. It is bent into. This angle θ is an angle at which the bent portion 15a does not come into contact with the free edge 8 when the flat diaphragm 9 as a flat speaker has a large amplitude due to the application of a large input and the free edge 8 made of soft foam is stretched and stretched. is set to . This angle θ is determined by the sizes of the flat diaphragm 9 and the free edge 8. Some examples are shown below.

[Example 1] Diameter of flat plate diaphragm 102mm, effective aperture when attached free edge 111mm, width of free edge 8
The bending angle θ of the surface material is 40 degrees or less when mm.

[Example 2] Diameter of flat plate diaphragm 192mm, effective aperture when attaching free edge 203mm, width of free edge 11
The bending angle θ of the surface material was also 40 degrees or less when expressed as mm.

Note that if the bent portion 15a of the surface material 15 is set at a right angle, that is, the angle θ is 0, the bent end surface will still become a knife edge, and the effect of providing the bent portion 15a will not be achieved, and this angle θ will be has at least several values, and the end surface of the bent portion 15a is R
It is necessary to have This R prevents the free edge 8 from being destroyed even if the free edge 8 makes strong contact.

Effects of the invention Since the planar speaker of the invention is constructed as described above, even if the free edge moves with an amplitude that causes it to protrude due to a large input, the free edge will not be destroyed by the surface material, and it will not be able to withstand the input. It can be made highly reliable and has great practical value.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a typical flat speaker;
The figure is a sectional view of the flat diaphragm portion of a conventional flat speaker, FIG. 3 is a sectional view showing the state at the time of large amplitude, and FIG. 4 is a flat diaphragm portion of an embodiment of the flat speaker of the present invention. FIG. 5 is an enlarged sectional view of the main part. 5... Magnetic circuit, 6... Frame, 8... Free edge, 9... Flat diaphragm, 12... Voice coil, 13... Magnetic gap, 14... Core material,
15, 16... surface material, 15a... bending part.

Claims (1)

[Scope of utility model registration request] A free edge made of soft foam is attached to the periphery of the frame connected to the magnetic circuit, and a flat diaphragm made of a core material with thin surface materials pasted on both sides is connected to this free edge. The voice coil that fits into the magnetic gap of the magnetic circuit is connected, and the surface material on the side to which the free edge of the flat diaphragm is pasted is made slightly larger than the outer diameter of the core material, and the part that protrudes outward from the core material is used to create a large amplitude vibration. A flat speaker made by bending the free edge to an angle that prevents it from touching when extended.